Not that I want to join the fray, but I also do freelance art and I advertise only through word of mouth. I give little discounts to people who blog or post about my work in order to bolster the awareness of my site. It's a great solid way to control your clientbase (good clients tend to refer good clients) and get a healthy position in the community. Forums count about 90% of my new business. Also I get past clients to comment in my threads on forums so that there is a central place for prospective clients to view my work. Just saying it's a valid approach.